Recent research has shown that, when properly formed and consolidated, wood pulp fibers can produce high performance structural products without the use of binders or adhesives. In the past, such products have been formed using solid shaping mandrels and having a wet-lay mold having the full drainage area exposed throughout the forming process. In these processes, water is drained between the mandrels, and thus drainage is slow and not well controlled, resulting in slow and non-uniform processes. Furthermore, there is not good control over fiber distribution during formation of the fiber mat. That is, there is no way to direct fibers from easily accessible areas of the mold to less accessible areas of the mold therefore producing a mat having a non-uniform distribution of fiber and widely different cross sections. Furthermore, due to the different conditions required for the formation of the fiber mat and for the consolidating and drying of that mat, the prior art processes require the fragile, wet-formed fiber mat to be transferred from a forming mold to a consolidating mold and may require several different transfers of web structure during consolidation and drying to achieve a desired density.
Prior art methods of consolidation use deformable rubber mandrels and/or an inflatable rubber mandrel which are not efficient heat and mass transfer means, and thus consolidation using the prior art techniques is inefficient and produces uncertain outcomes. Furthermore, the rubber-based molds are difficult to design and consolidation ratios in rubber-based molds are severely limited, often requiring multi-stage pressing in progressive molds, which is inefficient at best.